Alexion Secures Soliris Approval in China for Myasthenia Gravis

Rare Daily Staff

AstraZeneca said China’s National Medical Products Administration granted approval to the company to market Soliris to treatment adult patients with the rare autoimmune condition refractory generalized myasthenia gravis.

The decision makes Soliris the first and only complement inhibitor approved for the treatment of generalized myasthenia gravis (gMG) in China. The approval is for people who are anti-acetylcholine receptor (AChR) antibody-positive.

gMG is a rare, debilitating, chronic, autoimmune neuromuscular disease that leads to a loss of muscle function and severe weakness. Eighty percent of people with gMG are AChR antibody-positive meaning they produce specific antibodies (anti-AChR) that bind to signal receptors at the neuromuscular junction, the connection point between nerve cells and the muscles they control. This binding activates the complement system, which is essential to the body’s defense against infection, causing the immune system to attack the neuromuscular junction. This leads to inflammation and a breakdown in communication between the brain and the muscles.

Soliris is a first-in-class C5 complement inhibitor. The medication works by inhibiting the C5 protein in the terminal complement cascade, a part of the body’s immune system. When activated in an uncontrolled manner, the terminal complement cascade over-responds, leading the body to attack its own healthy cells. Soliris is administered intravenously every two weeks, following an introductory dosing period.

Soliris is approved in the United States, European Union, Japan, and China for the treatment of PNH, aHUS and certain adults with gMG. Additionally, Soliris is approved in the United States, European Union, and Japan for the treatment of certain adults with NMOSD.

The National Medical Products Administration based its approval on results from the phase 3 REGAIN trial. In the trial, Soliris demonstrated clinical benefit for patients with anti-AChR antibody-positive gMG who had previously failed immunosuppressive treatment and continued to suffer from significant unresolved disease symptoms.

The primary efficacy endpoint of change from baseline in MG-ADL total score at week 26, as well as the three secondary endpoints—changes from baseline in Quantitative Myasthenia Gravis (QMG), Myasthenia Gravis Composite score and Myasthenia Gravis Quality of Life 15-item scale—were assessed using a worst-rank analysis.

Patients who completed the randomized control period were eligible to continue into an open-label extension period evaluating the safety and efficacy of Soliris. Some 94 percent of patients who completed the REGAIN trial enrolled in the open-label extension, of which 56 continued to receive Soliris and 61 were switched from placebo to Soliris within two weeks of completing the REGAIN trial. The extension trial was completed in January 2019.

Improvements demonstrated during the initial six-month duration of the REGAIN trial were sustained over a treatment period of more than 130 weeks in the long-term open-label extension trial.

The safety and tolerability profile of Soliris was consistent throughout the primary treatment period and open-label extension. The most common adverse events in the primary treatment period were headaches and upper respiratory tract infection.